xref: /openbmc/linux/tools/perf/arch/s390/util/auxtrace.c (revision 9a29f5fc)
1 #include <stdbool.h>
2 #include <stdlib.h>
3 #include <linux/kernel.h>
4 #include <linux/types.h>
5 #include <linux/bitops.h>
6 #include <linux/log2.h>
7 #include <linux/zalloc.h>
8 
9 #include "../../util/evlist.h"
10 #include "../../util/auxtrace.h"
11 #include "../../util/evsel.h"
12 #include "../../util/record.h"
13 
14 #define PERF_EVENT_CPUM_SF		0xB0000 /* Event: Basic-sampling */
15 #define PERF_EVENT_CPUM_SF_DIAG		0xBD000 /* Event: Combined-sampling */
16 #define DEFAULT_AUX_PAGES		128
17 #define DEFAULT_FREQ			4000
18 
19 static void cpumsf_free(struct auxtrace_record *itr)
20 {
21 	free(itr);
22 }
23 
24 static size_t cpumsf_info_priv_size(struct auxtrace_record *itr __maybe_unused,
25 				    struct evlist *evlist __maybe_unused)
26 {
27 	return 0;
28 }
29 
30 static int
31 cpumsf_info_fill(struct auxtrace_record *itr __maybe_unused,
32 		 struct perf_session *session __maybe_unused,
33 		 struct perf_record_auxtrace_info *auxtrace_info __maybe_unused,
34 		 size_t priv_size __maybe_unused)
35 {
36 	auxtrace_info->type = PERF_AUXTRACE_S390_CPUMSF;
37 	return 0;
38 }
39 
40 static unsigned long
41 cpumsf_reference(struct auxtrace_record *itr __maybe_unused)
42 {
43 	return 0;
44 }
45 
46 static int
47 cpumsf_recording_options(struct auxtrace_record *ar __maybe_unused,
48 			 struct evlist *evlist __maybe_unused,
49 			 struct record_opts *opts)
50 {
51 	unsigned int factor = 1;
52 	unsigned int pages;
53 
54 	opts->full_auxtrace = true;
55 
56 	/*
57 	 * The AUX buffer size should be set properly to avoid
58 	 * overflow of samples if it is not set explicitly.
59 	 * DEFAULT_AUX_PAGES is an proper size when sampling frequency
60 	 * is DEFAULT_FREQ. It is expected to hold about 1/2 second
61 	 * of sampling data. The size used for AUX buffer will scale
62 	 * according to the specified frequency and DEFAULT_FREQ.
63 	 */
64 	if (!opts->auxtrace_mmap_pages) {
65 		if (opts->user_freq != UINT_MAX)
66 			factor = (opts->user_freq + DEFAULT_FREQ
67 				  - 1) / DEFAULT_FREQ;
68 		pages = DEFAULT_AUX_PAGES * factor;
69 		opts->auxtrace_mmap_pages = roundup_pow_of_two(pages);
70 	}
71 
72 	return 0;
73 }
74 
75 static int
76 cpumsf_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
77 			      struct record_opts *opts __maybe_unused,
78 			      const char *str __maybe_unused)
79 {
80 	return 0;
81 }
82 
83 /*
84  * auxtrace_record__init is called when perf record
85  * check if the event really need auxtrace
86  */
87 struct auxtrace_record *auxtrace_record__init(struct evlist *evlist,
88 					      int *err)
89 {
90 	struct auxtrace_record *aux;
91 	struct evsel *pos;
92 	int diagnose = 0;
93 
94 	*err = 0;
95 	if (evlist->core.nr_entries == 0)
96 		return NULL;
97 
98 	evlist__for_each_entry(evlist, pos) {
99 		if (pos->core.attr.config == PERF_EVENT_CPUM_SF_DIAG) {
100 			diagnose = 1;
101 			pos->needs_auxtrace_mmap = true;
102 			break;
103 		}
104 	}
105 
106 	if (!diagnose)
107 		return NULL;
108 
109 	/* sampling in diagnose mode. alloc aux buffer */
110 	aux = zalloc(sizeof(*aux));
111 	if (aux == NULL) {
112 		*err = -ENOMEM;
113 		return NULL;
114 	}
115 
116 	aux->parse_snapshot_options = cpumsf_parse_snapshot_options;
117 	aux->recording_options = cpumsf_recording_options;
118 	aux->info_priv_size = cpumsf_info_priv_size;
119 	aux->info_fill = cpumsf_info_fill;
120 	aux->free = cpumsf_free;
121 	aux->reference = cpumsf_reference;
122 
123 	return aux;
124 }
125